Whether primary or metastatic, tumors of the craniovertebral junction (CVJ) are rare and challenging.

OBJECTIVE: To examine the surgical indications, operative variables, and outcomes in patients with tumors of the CVJ undergoing occipitocervical (OC) stabilization.

METHODS: A single-institution, retrospective case series was performed from a prospectively maintained spine database. Patients with primary or metastatic tumors of the CVJ who underwent OC stabilization were identified. Out of 46 patients who underwent OC fusion, 39 were for tumor. Paired t-tests and Wilcoxon rank-sum tests were performed to assess for postoperative changes.

CONCLUSIONS: In patients with primary or metastatic tumor of the CVJ, OC stabilization using a cervical screw-rod system affixed to a midline-keel buttress plate, with or without posterior decompression, is a reliable method for CVJ stabilization in the oncologic setting. Improvement in pain and preservation of neurological function was seen.

Recent studies have demonstrated that periventricular tumor location is associated with poorer survival and that tumor location near the ventricle limits the extent of resection. This finding may relate to the perception that ventricular entry leads to further complications and thus surgeons may choose to perform less aggressive resection in these areas. However, there is little support for this view in the literature. This study seeks to determine whether ventricular entry is associated with more complications during craniotomy for brain tumor resection.

METHODS A retrospective analysis of patients who underwent craniotomy for tumor resection at Henry Ford Hospital between January 2010 and November 2012 was conducted. A total of 183 cases were reviewed with attention to operative entry into the ventricular system, postoperative use of an external ventricular drain (EVD), subdural hematoma, hydrocephalus, and symptomatic intraventricular hemorrhage (IVH).

CONCLUSIONS There are more complications associated with ventricular entry during brain tumor resection than in nonviolated ventricular systems. Better strategies for management of periventricular tumor resection should be actively sought to improve resection and survival for these patients.

Lesions of the superior cerebellar surface, pineal region, lateral and dorsal midbrain and mesial temporal lobe are challenging to treat and often require neurosurgical intervention.

Methods The paramedian variation of the supracerebellar infratentorial approach utilizes the downward slope of the cerebellum to facilitate exposure and the lower density of cerebellar bridging veins away from the midline decreases the need to sacrifice larger venous channels. We also discuss our experiences with the approach, and some of the drawbacks and nuances that we have encountered as it has evolved over the years.

Conclusions This approach is versatile and effective and the authors’ surgical approach of choice for resecting these challenging lesions.

Cranioplasty after decompressive craniectomy (DC) is routinely performed for reconstructive purposes and has been recently linked to improved cerebral blood flow (CBF) and neurological function.

OBJECTIVE: To systematically review all available literature to evaluate the effect of cranioplasty on CBF and neurocognitive recovery.

METHODS: A PubMed, Google Scholar, and MEDLINE search adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines included studies reporting patients who underwent DC and subsequent cranioplasty in whom cerebral hemodynamics were measured before and after cranioplasty.

RESULTS: The search yielded 21 articles with a total of 205 patients (range 3–76 years) who underwent DC and subsequent cranioplasty. Two studies enrolled 29 control subjects for a total of 234 subjects. Studies used different imaging modalities, including CT perfusion (n = 10), Xenon-CT (n = 3), single-photon emission CT (n = 2), transcranial Doppler (n = 6), MR perfusion (n = 1), and positron emission tomography (n = 2). Precranioplasty CBF evaluation ranged from 2 days to 6 months; postcranioplasty CBF evaluation ranged from 7 days to 6 months. All studies demonstrated an increase in CBF ipsilateral to the side of the cranioplasty. Nine of 21 studies also reported an increase in CBF on the contralateral side.Neurological function improved in an overwhelming majority of patients after cranioplasty.

CONCLUSION: This systematic review suggests that cranioplasty improves CBF following DC with a concurrent improvement in neurological function. The causative impact of CBF on neurological function, however, requires further study.

Idiopathic intracranial hypertension (IIH) is characterised by an increased intracranial pressure (ICP) in the absence of any central nervous system disease or structural abnormality and by normal CSF composition. Management becomes complicated once surgical intervention is required. Venous sinus stenosis has been suggested as a possible aetiology for IIH. Venous sinus stenting has emerged as a possible interventional option. Evidence for venous sinus stenting is based on elimination of the venous pressure gradient and clinical response. There have been no studies demonstrating the immediate effect of venous stenting on ICP.

Methods Patients with a potential or already known diagnosis of IIH were investigated according to departmental protocol. ICP monitoring was performed for 24 h. When high pressures were confirmed, CT venogram and catheter venography were performed to look for venous stenosis to demonstrate a pressure gradient. If positive, venous stenting would be performed and ICP monitoring would continue for a further 24 h after deployment of the venous stent.

Results Ten patients underwent venous sinus stenting with concomitant ICP monitoring. Nine out of ten patients displayed an immediate reduction in their ICP that was maintained at 24 h. The average reduction in mean ICP and pulsatility was significant (p = 0.003). Six out of ten patients reported a symptomatic improvement within the first 2 weeks.

Conclusions Venous sinus stenting results in an immediate reduction in ICP. This physiological response to venous stenting has not previously been reported. Venous stenting could offer an alternative treatment option in correctly selected patients with IIH.

An understanding of the present standing of surgery, surgical results and the role in altering the future morbidity and mortality of untreated brain arteriovenous malformations (bAVMs) is appropriate considering the myriad alternative management pathways (including radiosurgery, embolization or some combination of treatments), varying risks and selection biases that have contributed to confusion regarding management. The purpose of this review is to clarify the link between the incidence of adverse outcomes that are reported from a management pathway of either surgery or no intervention with the projected risks of surgery or no intervention.

Methods A critical review of the literature was performed on the outcomes of surgery and non-intervention for bAVM. An analysis of the biases and how these may have influenced the outcomes was included to attempt to identify reasonable estimates of risks.

Results In the absence of treatment, the cumulative risk of future hemorrhage is approximately 16% and 29% at 10 and 20 years after diagnosis of bAVM without hemorrhage and 35% and 45% at 10 and 20 years when presenting with hemorrhage (annualized, this risk would be approximately 1.8% for unruptured bAVMs and 4.7% for 8 years for bAVMs presenting with hemorrhage followed by the unruptured bAVM rate). The cumulative outcome of these hemorrhages depends upon whether the patient remains untreated and is allowed to have a further hemorrhage or is treated at this time. Overall, approximately 42% will develop a new permanent neurological deficit or death from a hemorrhagic event. The presence of an associated proximal intracranial aneurysm (APIA) and restriction of venous outflow may increase the risk for subsequent hemorrhage. Other risks for increased risk of hemorrhage (age, pregnancy, female) were examined, and their purported association with hemorrhage is difficult to support. Both the Spetzler-Martin grading system (and its compaction into the Spetzler-Ponce tiers) and Lawton-Young supplementary grading system are excellent in predicting the risk of surgery. The 8-year risk of unfavorable outcome from surgery (complication leading to a permanent new neurological deficit with a modified Rankin Scale score of greater than one, residual bAVM or recurrence) is dependent on bAVM size, the presence of deep venous drainage (DVD) and location in critical brain (eloquent location). For patients with bAVMs who have neither a DVD nor eloquent location, the 8-year risk for an unfavorable outcome increases with size (increasing from 1 cm to 6 cm) from 1% to 9%. For patients with bAVMwho have either a DVD or eloquent location (but not both), the 8- year risk for an unfavorable outcome increases with the size (increasing from 1 cm to 6 cm) from 4% to 35%. For patients with bAVM who have both a DVD and eloquent location, the 8-year risk for unfavorable outcome increases with size (increasing from 1 cm to 3 cm) from 12% to 38%.

Conclusion Patients with a Spetzler-Ponce A bAVM expecting a good quality of life for the next 8 years are likely to do better with surgery in expert centers than remaining untreated. Ongoing research is urgently required on the outcome of management pathways for bAVM.

Risk factors for pre- and postoperative seizures in supratentorial meningiomas are understudied compared to other brain tumors.

OBJECTIVE: To report seizure frequency and identify factors associated with pre- and postoperative seizures in a large single-center population study of patients undergoing resection of supratentorial meningioma.

Three different types of anti-siphon devices (ASDs) have been developed to counteract siphoning induced overdrainage in upright posture. However, it is not known how the different ASDs affect CSF dynamics under the complex pressure environment seen in clinic due to postural changes. We investigated which ASDs can avoid overdrainage in upright posture best without leading to CSF accumulation.

Methods Three shunts each of the types Codman Hakim with SiphonGuard (flow-regulated), Miethke miniNAV with proSA (gravitational), and Medtronic Delta (membrane controlled) were tested. The shunts were compared on a novel in vitro setup that actively emulates the physiology of a shunted patient. This testing method allows determining the CSF drainage rates, resulting CSF volume, and intracranial pressure in the supine, sitting, and standing posture.

Results The flow-regulated ASDs avoided increased drainage by closing their primary flow path when drainage exceeded 1.39 ± 0.42 mL/min. However, with intraperitoneal pressure increased in standing posture, we observed reopening of the ASD in 3 out of 18 experiment repetitions. The adjustable gravitational ASDs allow independent opening pressures in horizontal and vertical orientation, but they did not provide constant drainage in upright posture (0.37 ± 0.03 mL/min and 0.26 ± 0.03 mL/min in sitting and standing posture, respectively). Consequently, adaptation to the individual patient is critical. The membrane-controlled ASDs stopped drainage in upright posture. This eliminates the risk of overdrainage, but leads to CSF accumulation up to the volume observed without shunting when the patient is upright.

Conclusions While all tested ASDs reduced overdrainage, their actual performance will depend on a patient’s specific needs because of the large variation in the way the ASDs influence CSF dynamics: while the flow-regulated shunts provide continuous drainage in upright posture, the gravitational ASDs allow and require additional adaptation, and the membrane-controlled ASDs show robust siphon prevention by a total stop of drainage.

Endovascular embolization is the treatment of choice for carotid-cavernous fistulas (CCFs), but failure to catheterize the cavernous sinus may occur as a result of vessel tortuosity, hypoplasia, or stenosis. In addition to conventional transvenous or transarterial routes, alternative approaches should be considered. The authors present a case in which a straightforward route to the CCF was accessed via transsphenoidal puncture of the cavernous sinus in a neurosurgical hybrid operating suite.

This 82-year-old man presented with severe chemosis and proptosis of the right eye. Digital subtraction angiography revealed a Type B CCF with a feeding artery arising from the meningohypophyseal trunk of the right cavernous segment of the internal carotid artery. The CCF drained through a thrombosed right superior ophthalmic vein that ended deep in the orbit; there were no patent sinuses or venous plexuses connecting to the CCF. An endoscope-assisted transsphenoidal puncture created direct access to the nidus for embolization. Embolic agents were deployed through the puncture needle to achieve complete obliteration.

Endoscope-assisted transsphenoidal puncture of the cavernous sinus is a feasible alternative to treat difficult-to-access CCFs in a neurosurgical hybrid operating suite.

Idiopathic normal pressure hydrocephalus (iNPH) is characterized by ventriculomegaly, gait difficulty, incontinence, and dementia. The symptoms can be ameliorated by CSF drainage. The object of this study was to identify factors associated with shunt-responsive iNPH.

METHODS The authors reviewed the medical records of 529 patients who underwent shunt placement for iNPH at their institution between July 2001 and March 2015. Variables associated with shunt-responsive iNPH were identified using bivariate and multivariate analyses. Detailed alcohol consumption information was obtained for 328 patients and was used to examine the relationship between alcohol and shunt-responsive iNPH. A computerized patient registry from 2 academic medical centers was queried to determine the prevalence of alcohol abuse among 1665 iNPH patients.